Battery Charging Advice

[jsmaeb1215]

Hey everyone. Very new to boating but trying to do my best to learn as much possible from the forums.

I just picked a 1996 Stingray 556zp with a 3.0 merc. Well on our way in from enjoying the day I noticed my fish finder died and the boat turned over a bit slow. It seems my #1 battery was pretty much dead, 11.9 volts. All seemed well on battery #2 (Installed 2nd battery a few weeks ago with one of those 1-2-all-off switches from bass pro, sure glad I did that!). We pretty much drop in the water cruise for 20 minutes to our spot then chill for a few hours. Is that enough time to really charge my main battery? Should I look to keep these batteries on a trickle charger, I have a small one I use for my motorcycle?

My concern is my charging system. I just installed a new alternator 2 weekends ago so I should be ok there. From what I have read these marine 3 or 4 wire alternators are a bit different then automotive and only charge when needed, is this correct? I'm half tempted to pull the alternator and have it tested, then possibly have both batteries load tested as I really have no idea how the previous owner took care of them.

I appreciate any input!

 

[Silvertip]

Re: Battery Charging Advice

The boat likely has a voltmeter. pay attention to it. If it is not reading above 13.5 volts at 2000 rpm or so it is not charging.

 

[Grandad]

Re: Battery Charging Advice

Hey everyone. Very new to boating but trying to do my best to learn as much possible from the forums.

I just picked a 1996 Stingray 556zp with a 3.0 merc. Well on our way in from enjoying the day I noticed my fish finder died and the boat turned over a bit slow. It seems my #1 battery was pretty much dead, 11.9 volts. All seemed well on battery #2 (Installed 2nd battery a few weeks ago with one of those 1-2-all-off switches from bass pro, sure glad I did that!). We pretty much drop in the water cruise for 20 minutes to our spot then chill for a few hours. Is that enough time to really charge my main battery? Should I look to keep these batteries on a trickle charger, I have a small one I use for my motorcycle?

My concern is my charging system. I just installed a new alternator 2 weekends ago so I should be ok there. From what I have read these marine 3 or 4 wire alternators are a bit different then automotive and only charge when needed, is this correct? I'm half tempted to pull the alternator and have it tested, then possibly have both batteries load tested as I really have no idea how the previous owner took care of them.

I appreciate any input!

How old is #1 battery? Has it been stored properly? I'd start with a load test on it, but if it's more than 4 years old, I wouldn't expect it to be reliable. As you've already appreciated the new battery, you know that peace of mind could balance the replacement cost. I look at a battery this way; if a $100 battery lasts 5 years, that's $20 a year. Scrapping it one year sooner costs you only $20. - Grandad

 

[bruceb58]

Re: Battery Charging Advice

You need to keep your battery fully charged at all times. If it is stored discharged, even slightly, it will dramatically reduce the life of the battery.

 

[UncleWillie]

Re: Battery Charging Advice

A low battery will not charge in 20 minutes of Engine run time, or on any charger in 20 minutes.
A "Trickle" charger will will take many days to recharge the battery.
If you only use it once a week you might get away with it.
A Smart charger will charge the battery in half a day and then go into Trickle/Maintenance mode to maintain the battery until you return.

I have a Full Size charger but also This One.
It is silent, No Fan, and makes no heat when in Maintenance mode.
A totally Dead Battery will take over a day to recharge, but much faster than a "Trickle" Charger.

 

[NYBo]

Re: Battery Charging Advice

My concern is my charging system. I just installed a new alternator 2 weekends ago so I should be ok there. From what I have read these marine 3 or 4 wire alternators are a bit different then automotive and only charge when needed, is this correct? I'm half tempted to pull the alternator and have it tested, then possibly have both batteries load tested as I really have no idea how the previous owner took care of them.

A marine alternator works exactly the same as the one in a car: The regulator keeps the battery from overcharging.

Having the batteries load-tested is a good idea. Your main battery may be dead or dying from being run down so far.

 

[jsmaeb1215]

Re: Battery Charging Advice

Appreciate all the input. Age of battery #1 is unknown as I can't seem to find a date on it. Battery #2 looks to be from 2011 which is also a bit old but seems to be doing ok. I think my best step is to get a load test done on them.

My charging system concerns me a bit. Using my volt meter I have never once seen more 12.3 volts at my batteries while the boat is running, this is with the old alternator and new. With cars I am use to seeing 13.5-14 volts at the battery while running. I am wondering if something is up with my charging system. Maybe the regulator is going bad, or is that built into the alternator itself? I wish the old trick of disconnecting the battery while its running worked with boats, but from what I hear it can cause major issues.

 

[UncleWillie]

Re: Battery Charging Advice

Unless the battery voltage is above ~13.5v, the battery is NOT being charged.
Above 14v is expected and common. Just like in Cars.
A fully charged battery will measure ~12.6v at rest. 12.3 is ~75% charged.

You have a problem and are NOT charging the batteries.
In Fact, the alternator is not working at all.

The Battery is weak because it is not fully charged.
If it has gone this long without being charged, it is acting like a very good battery.

 

[bruceb58]

Re: Battery Charging Advice

I wish the old trick of disconnecting the battery while its running worked with boats, but from what I hear it can cause major issues.

That old trick never worked with anything. Good way to fry your alternator/regulator. If you have done this EVER, it will explain your no output problem.

 

[jsmaeb1215]

Re: Battery Charging Advice

That old trick never worked with anything. Good way to fry your alternator/regulator. If you have done this EVER, it will explain your no output problem.

Done it on cars for many years without any issue but I won't do again, learn something new everyday!

Both the new and old alternator don't seem to put out much of anything. Could I have a bad regulator? I did verify that sensor wire is seeing 12 volts from the battery. If I understand these 3 wire alternators correctly that means it should be charging.

Maybe I should test at the power wire on the alternator to see if its outputting anything.

 

[UncleWillie]

Re: Battery Charging Advice

Did it on cars for many years without any issue but I won't do again, learn something new everyday!

Both the new and old alternator don't seem to put out much of anything. Could I have a bad regulator? I did verify that the sensor wire is seeing 12 volts from the battery. If I understand these 3 wire alternators correctly that means it should be charging.

Just what is this "Trick" supposed to accomplish?

You can't charge a 12 volt battery until you get the voltage above the Float Voltage of ~13.4v.
The chemical reaction needed to charge, will not reverse, if below this threshold level.
14+ volts is needed to get the charge time down to 12 hours or less.

When trouble shooting a charging issue don't just state that you see "12 Volts".
Be specific; 12.3v and 12.8v are a world of difference.

 

[jsmaeb1215]

Re: Battery Charging Advice

Just what is this "Trick" supposed to accomplish?

You can't charge a 12 volt battery until you get the voltage above the Float Voltage of ~13.4v.
The chemical reaction needed to charge, will not reverse, if below this threshold level.
14+ volts is needed to get the charge time down to 12 hours or less.

When trouble shooting a charging issue don't just state that you see "12 Volts".
Be specific; 12.3v and 12.8v are a world of difference.

If you disconnect the battery while its running and it dies, then you know the alternator is dead, if it stays running then you know its ok. Never realized it could cause an electrical issue though.

I see 12.3 volts when the boat is off and 11.9-12.0 when running, and that is on either of the batteries.

I am also wondering if possibly this is just an issues with the exciter wire. Maybe its not properly exciting the alternator, which would also explain why the old one did the same thing. Does anyone know what provides the exciter wire with power? Should I just supply 12 volts to that wire and see if the alternator starts producing power?

 

[UncleWillie]

Re: Battery Charging Advice

You know the alternator is dead because the battery voltage goes DOWN with the engine running!

The way I understand it.

The Big Battery/Alternator wire will have Battery (12) volts on it Always.
One of the other two wires will show ~12v Key On, Engine Off. (0 volts on the other wire)
Both will show ~12v Engine Running.

Don't Quote me on that.

Before you start redesigning your electrical system; trace the wires.
This could be as simple as a fuse.

 

[jsmaeb1215]

Re: Battery Charging Advice

You know the alternator is dead because the battery voltage goes DOWN with the engine running!

The way I understand it.

The Big Battery/Alternator wire will have Battery (12) volts on it Always.
One of the other two wires will show ~12v Key On, Engine Off. (0 volts on the other wire)
Both will show ~12v Engine Running.

Don't Quote me on that.

That's what I was thinking. My best guess at the moment is on the exciter wire not getting 12v. I have read on a few forums (automative) that the exciter wire only gets 6-8 volts, either way I am not seeing any.

When I get home I will trace the exciter wire down and see if I cam getting 12v from it. I really appreciate all the input! Great community going on here.

 

[jsmaeb1215]

Re: Battery Charging Advice

That's what I was thinking. My best guess at the moment is on the exciter wire not getting 12v. I have read on a few forums (automative) that the exciter wire only gets 6-8 volts, either way I am not seeing any.

When I get home I will trace the exciter wire down and see if I cam getting 12v from it. I really appreciate all the input! Great community going on here.

Well did a bit of testing.

Before Starting each battery had 11.9 volts.

After starting I was at 11.8 on the battery being used.

On the alternator
- Sensor - 11.8 volts
- Exciting - 12 to 12.3 volts, seemed to jump around quite a bit
(This is were it gets weird)
- Orange Power - 23-24 volts

After seeing that I tested a few more times and it was still 23-24. I shut the boat off, and eliminated my 2 battery setup, and went back to just a single battery. Re-tested and still same numbers. I am quite baffled at this point.

I tested on my car to make sure my meter is still working aok. 12.4 before starting and 13.9 while running, I don't think anything is wrong with my meter.

 

[bruceb58]

Re: Battery Charging Advice

I am assuming your orange wire is the large wire that feeds your battery. Sounds like its not hooked up to your battery at all. No load. Maybe show a picture of what you are measuring.

By the way, if you disconnect your battery while the engine is running, the voltage output of the alternator will go extremely high and that what cooks the alternator and any electronic devices along with it if the voltage goes above their input ratings.

 

[jsmaeb1215]

Re: Battery Charging Advice

I am assuming your orange wire is the large wire that feeds your battery. Sounds like its not hooked up to your battery at all. No load. Maybe show a picture of what you are measuring.

By the way, if you disconnect your battery while the engine is running, the voltage output of the alternator will go extremely high and that what cooks the alternator and any electronic devices along with it if the voltage goes above their input ratings.

Yep the Orange wire is the one I believe should be feeding the battery. Here is a picture of it at the alternator.



Here is a picture of it at the starter.



I get 11.8 volts at the orange wire at the starter. I must have a break in that wire some place.

Is it normal for that power wire coming from the alternator to be connected to the starter and not the battery? Just want to make sure the previous owner doesn't have any funny wiring going on.

 

[bruceb58]

Re: Battery Charging Advice

It normally goes to the starter but there isn't anything wrong with having it connect to the battery as long as you have only one battery.

 

[UncleWillie]

Re: Battery Charging Advice

What we have here, is Failure to Communicate (the Current).

With the engine running, On each end of the Orange wire...
Measure the voltage on the Threaded stud.
Measure the voltage on the Metal of the Crimped Ring Lugs.
Measure the Voltage on the exposed ends of the Copper Wire inside of the Ring lugs.

The Open Connection will be where the change happens.

Take care to disturb the Orange wire as little as possible.
One small bump may bring the whole thing back to life, and then you won't know where the problem was.

The 24 volts you see is the Alternator going out of regulation because it is NOT Electrically connected to the Battery.
This is also a perfect demonstration of why you do not want to disconnect the Battery from a running Alternator.
That 24 volts would be present on your Engine's Computer, and your stereo radio, among other expensive things.

The location of the Orange Wire from the Alternator to the Starter is completely normal.

 

[jsmaeb1215]

Re: Battery Charging Advice

What we have here, is Failure to Communicate (the Current).

With the engine running, On each end of the Orange wire...
Measure the voltage on the Threaded stud.
Measure the voltage on the Metal of the Crimped Ring Lugs.
Measure the Voltage on the exposed ends of the Copper Wire inside of the Ring lugs.

The Open Connection will be where the change happens.

Take care to disturb the Orange wire as little as possible.
One small bump may bring the whole thing back to life, and then you won't know where the problem was.

The 24 volts you see is the Alternator going out of regulation because it is NOT Electrically connected to the Battery.
This is also a perfect demonstration of why you do not want to disconnect the Battery from a running Alternator.
That 24 volts would be present on your Engine's Computer, and your stereo radio, among other expensive things.

The location of the Orange Wire from the Alternator to the Starter is completely normal.

I ended up replacing the orange wire with a new nice 10gauge wire and all is well again. I am getting 14v at the batteries and at the alternator, overall seems to be running much better. I appreciate all the advice!!